Читать книгу Workshop Projects - Jeff Jacobson - Страница 11
Moving Up to the Top
ОглавлениеThe top is basically a three-layer sandwich that’s banded with thick maple rails. First, two panels of fir plywood (pieces 8 and 9) are laminated together to make the top stable and heavy, and then, above the plywood, a layer of removable hardboard (piece 10) is added to take the dings and dents suffered by any workbench. When the hardboard becomes too scarred from working at the bench, remove it and use it as a template for making a new one. To complete the top assembly, maple rails (pieces 11) are attached to the plywood, giving the top an attractive edge and a durable surface for anchoring the T-slot tracks (pieces 15).
Figure 2: Batten boards, which have a curve of about ⅛" on the bottom edge, are used to apply pressure at the middle of a wide panel assembly.
Start building your top by cutting the two plywood panels to size and gluing them together. Use a brush or roller to spread yellow glue over both mating surfaces, and then center the smaller panel on top of the larger one. Next, to keep the panels from slipping out of position, drive a brad into the assembly at each corner of the smaller panel. Clamping the plywood requires consistent pressure throughout the lamination, so make sure you’ve precut a bunch of curved batten boards to apply pressure in the middle of the panels (see Figure 2).
Rip and crosscut your maple to size for the rails, and then drill 1½"-deep holes in one edge of each piece, as shown in the dog hole locations drawing on page 2. After drilling the 1" holes, install a ¾" dado blade in your table saw to cut a 1"-deep x 2"-wide rabbet in the other edge of each rail (see the drawing at right). Make several passes to complete each rabbet, making sure to clamp your protective wood face to the saw fence.
The maple rails should now be glued and screwed to the upper plywood panel. I recommend first clamping the rails without glue to the plywood and then drilling countersunk pilot holes through the plywood into the rail (drill seven evenly spaced holes along each rail). When you’ve finished drilling, release the clamps, spread glue in the rail rabbets, and reclamp the assembly. With everything in place, drive the screws, and then clean up any glue squeeze-out, especially along the inside edge of the rail.
The final piece to fit into the top is the tempered hardboard. Cut the sheet to fit between the rails as snugly as possible, and then drill countersunk pilot holes along its edges for the screws that will secure it to the plywood. Fasten it down.
Material List – Workbench
| T x W x L | ||
| 1 | Legs (4) | 3" x 3½" x 32¼" |
| 2 | Side Aprons (2) | 1½" x 3½" x 76" |
| 3 | Top Supports (2) | 1½" x 3½" x 22½" |
| 4 | Side Stretchers (2) | 1½" x 3½" x 54" |
| 5 | End Aprons (2) | 1½" x 3½" x 21" |
| 6 | End Stretchers (2) | 1½" x 3½" x 21" |
| 7 | Leveling Glides (1 Set) | Heavy Duty |
| 8 | Top Panel (1) | ¾" x 22" x 80" |
| 9 | Bottom Panel (1) | ¾" x 18" x 80" |
| 10 | Hardboard (1) | ¼" x 22" x 80" |
| 11 | Maple Rails (2) | 1¾" x 6" x 80" |
| 12 | Endcap (1) | 1¾" x 1¾" x 30" |
| 13 | Inside Vise Jaw (1) | 1¾" x 5¾" x 30" |
| 14 | Outside Vise Jaw (1) | 2" x 5¾" x 30" |
| 15 | T-Slot Tracks (4) | 13/32" x 13/16" x 40" |
| 16 | Screws (30) | #6-1" Panhead |
| 17 | Lag Bolts/Washers (3) | 3/8" x 2½" |
| 18 | Screws (15) | #12-2½" |
| 19 | Dog Heads (4) | ½" x 2" x 2" |
| 20 | Dog Dowels (4) | 1" Dia. x 1½" Long |
Now, for the T-slot system. The efficient use of this bench really revolves around jigs made with a T-bolt and a knob clamp. The T-bolt slides in a metal track that’s secured to the bench with screws, and then the knob on the bolt is tightened to hold the jig in place. The track will last through a lifetime of use.
Installing the metal track requires a simple 13/16"-wide x 3/8"-deep groove. Make sure the groove depth is accurate: If it’s too shallow, the track will stick up into the work surface, and if it’s too deep, the accessories will pull the track out of the groove. Lay out the track grooves on the maple rails, as shown in the end view detail on page 4. Then, chuck a ½" straight bit in your router, and attach a straightedge guide. Now, rout one 3/8"-deep pass for each track, and then reset the edge guide to make a second pass, widening the grooves to 13/16".
Since the track comes in 40" lengths, this bench requires four pieces to make up the two parallel slots. To secure the tracks, set them into the grooves, and drill 5/32"-diameter holes every 6". Next, drive a #6-1" panhead screw (pieces 16) into each hole. If the track overhangs the end of the bench, cut the excess off with a hacksaw.
Figure 3: A drilling jig ensures accurate dog holes; just be sure to switch the fence for each row.
